* first steps in async

src/AasxPluginAssetInterfaceDesc/AidHttpConnection.cs

@@ -49,7 +49,7 @@ override public void Close()
             // nothing to do, this simple http connection is stateless
         }
 
-        override public int UpdateItemValue(AidIfxItemStatus item)
+        override public async Task<int> UpdateItemValueAsync(AidIfxItemStatus item)
         {
             // access
             if (item?.FormData?.Href?.HasContent() != true
@@ -67,16 +67,12 @@ override public int UpdateItemValue(AidIfxItemStatus item)
                     var url = new Uri(TargetUri, item.FormData.Href);
 
                     // get response (synchronously)
-                    var task = Task.Run(() => Client.GetAsync(url));
-                    task.Wait();
-                    var response = task.Result;
+                    var response = await Client.GetAsync(url);
 
                     // ok?
                     if (response.IsSuccessStatusCode)
                     {
-                        var task2 = Task.Run(() => response.Content.ReadAsStringAsync());
-                        task2.Wait();
-                        var strval = task2.Result;
+                        var strval = await response.Content.ReadAsStringAsync();
                         item.Value = strval;
                         res = 1;
                     }

src/AasxPluginAssetInterfaceDesc/AidInterfaceService.cs

@@ -18,6 +18,7 @@ This source code may use other Open Source software components (see LICENSE.txt)
 using System.Linq;
 using System.Reflection;
 using System.Text;
+using System.Threading.Tasks;
 
 namespace AasxPluginAssetInterfaceDescription
 {
@@ -44,7 +45,7 @@ public void StartOperation(LogInstance log, AidAllInterfaceStatus allInterfaceSt
 			_allInterfaceStatus = allInterfaceStatus;
 
 			_dispatcherTimer = new System.Timers.Timer(_timerTickMs);
-			_dispatcherTimer.Elapsed += DispatcherTimer_Tick;
+			_dispatcherTimer.Elapsed += DispatcherTimer_TickAsync;
 			_dispatcherTimer.Enabled = true;
 			_dispatcherTimer.Start();
 		}
@@ -55,7 +56,7 @@ public void StartOperation(LogInstance log, AidAllInterfaceStatus allInterfaceSt
 
 		private bool _inDispatcherTimer = false;
 
-		private void DispatcherTimer_Tick(object sender, EventArgs e)
+		private async void DispatcherTimer_TickAsync(object sender, EventArgs e)
 		{
 			// access
 			if (_allInterfaceStatus == null || _inDispatcherTimer)
@@ -67,15 +68,14 @@ private void DispatcherTimer_Tick(object sender, EventArgs e)
 			// call cyclic tasks
 			try
 			{
-				_allInterfaceStatus.UpdateValuesContinousByTick();
+				await _allInterfaceStatus.UpdateValuesContinousByTickAsyc();
 			} catch (Exception ex)
 			{
 				;
 			}
 
 			// release mutex
 			_inDispatcherTimer = false;
-
 		}
 	}
 }

src/AasxPluginAssetInterfaceDesc/AidInterfaceStatus.cs

@@ -190,14 +190,28 @@ virtual public void Close()
         }
 
         /// <summary>
-        /// Tris to update the value (by polling).
+        /// Tries to update the value (by polling).
         /// </summary>
         /// <returns>Number of values changed</returns>
         virtual public int UpdateItemValue(AidIfxItemStatus item)
         {
             return 0;
         }
 
+        /// <summary>
+        /// Tries to update the value (by polling).
+        /// </summary>
+        /// <returns>Number of values changed</returns>
+        virtual public async Task<int> UpdateItemValueAsync(AidIfxItemStatus item)
+        {
+            await Task.Yield();
+            return 0;
+        }
+
+        // <summary>
+        /// Tries to update the value (by polling). Async opion is preferred.
+        /// </summary>
+        /// <returns>Number of values changed</returns>
         virtual public void PrepareContinousRun(IEnumerable<AidIfxItemStatus> items)
         {
 
@@ -401,7 +415,7 @@ public void StopContinousRun()
         /// <summary>
         /// In continous run, will fetch values for polling based technologies (HTTP, Modbus, ..).
         /// </summary>
-        public void UpdateValuesContinousByTick()
+        public async Task UpdateValuesContinousByTickAsyc()
         {
             // access allowed
             if (!ContinousRun)
@@ -421,9 +435,19 @@ public void UpdateValuesContinousByTick()
                     if (ifc?.Connection?.IsConnected() != true)
                         continue;
 
-                    // go thru all items
+                    // go thru all items (sync)
                     foreach (var item in ifc.Items.Values)
                         ifc.ValueChanges += (UInt64) ifc.Connection.UpdateItemValue(item);
+
+                    // go thru all items (async)
+                    // see: https://www.hanselman.com/blog/parallelforeachasync-in-net-6
+                    await Parallel.ForEachAsync(
+                        ifc.Items.Values, 
+                        new ParallelOptions() { MaxDegreeOfParallelism = 10 }, 
+                        async (item, token) =>
+                    {
+                        ifc.ValueChanges += (UInt64) (await ifc.Connection.UpdateItemValueAsync(item));
+                    });
                 }
             }
         }